81351457 has 4 divisors (see below), whose sum is σ = 88747056. Its totient is φ = 73955860.

The previous prime is 81351451. The next prime is 81351461. The reversal of 81351457 is 75415318.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 81351457 - 2⁷ = 81351329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81351451) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3697783 + ... + 3697804.

It is an arithmetic number, because the mean of its divisors is an integer number (22186764).

Almost surely, 2^81351457 is an apocalyptic number.

It is an amenable number.

81351457 is a deficient number, since it is larger than the sum of its proper divisors (7395599).

81351457 is a wasteful number, since it uses less digits than its factorization.

81351457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7395598.

The product of its digits is 16800, while the sum is 34.

The square root of 81351457 is about 9019.5042546694. The cubic root of 81351457 is about 433.2997567015.

The spelling of 81351457 in words is "eighty-one million, three hundred fifty-one thousand, four hundred fifty-seven".